Protein or polypeptide immunogens such as hepatitis B surface antigen are formulated for human vaccine use by adsorption to aluminum hydroxide (alum). Once the protein has been insolubilized by the adsorption to alum it is impossible to further process or reprocess the immunogen without removing the alum. Dissolution of the protein-alum complex may be necessitated by compromised sterility or a requirement to re-work the vaccine. The inability to re-work or resterilize the vaccine may result in a substantial economic loss if it must be discarded. In the past, the alum was removed by treatment of the protein-alum complex with a strong acid or base capable of dissolving the alum. While the acid or base efficiently dissolved the alum, it also destroyed the immunogenicity of the protein and rendered it ineffective as a vaccine.